If the cinder block aka brick was tested to see where the brick was manufactured, and shipped, my crazy head tells me that there is a video camera with someone picking it up. Don't ask why I feel this, I just do.
I understand your focus on the cinder block....but these are laying all over the area. The field across the street...the area in the thick area around the mh....across the canal near the bus stop in the Manufactured Home community...along the RR tracks sporadically laying around. In the high grass I tripped over during a search.
I know you have researched the manufacture's of cinder blocks, but I really think concentrating on the BRICKED cinder block... is futile. JMO
Are Cinder blocks used at all for leveling mh's...could that be why they are all over the place?
I would never question your reason's for this and it would be a blessing if your focus on this lead to WTH happened.